Positron emission tomography (PET) imaging is a functional imaging modality that generates and displays three-dimensional (3-D) tomographic images of distribution of radioactive isotopes injected into the body. While PET images provide quantitative representations of isotope distribution, they lack structural information about the anatomical structure of the surrounding tissues where the isotope is distributed. Computed tomography (CT) imaging generates 3-D tomographic images with structural information of anatomical tissue. PET and CT images have been combined (e.g., overlaid, fused, etc.) to provide functional information with an anatomical frame of reference.
PET and CT datasets can be acquired individually with a standalone PET gantry and a standalone CT gantry. PET and CT datasets can also be acquired with a single system that includes both a PET gantry portion and a CT gantry portion. With this configuration, the PET and CT gantry portions are physically spaced apart from each other along the scanning axis and have separate and distinct imaging planes. The PET and CT gantry portions are consecutively employed, moving the subject or object in between scans from one gantry portion to the other, and PET and CT datasets are acquired independently in that the PET dataset is not acquired with the CT gantry portion, and the CT dataset is not acquired with the PET gantry portion.
Unfortunately, with the above noted configurations, patient movement, voluntary and/or involuntary, between PET and CT scans may result in miss-registration of combined PET and CT images. Furthermore, the patient is moved from one gantry/gantry portion to the other gantry/gantry portion between PET and CT scans, which increases total scan time. Moreover, standalone and connected systems require two separate gantries/gantry portions and supporting hardware for each, each adding to manufacturing and/or service complexity and/or cost.